Our cities need smarter green and blue infrastructure, not just more of them

Community garden in Chiswick, London.

As cities grow, denser, hotter, and more vulnerable to extreme weather, we have all heard the same hopeful message: “nature can save us”. Trees cool streets. Wetlands absorb floods. Parks improve air quality and bring communities together. In other words, Green and Blue Infrastructure (GBI), from urban forests, street trees, parks to rivers and wetlands, has become the new hero of sustainable cities.

So why, despite all this enthusiasm, are so many cities still missing out on the real potential of GBI? And if GBIs are so good for our health and our cities, how come we don’t see them everywhere?

These were the exact questions on my mind in my work as a Research Fellow at the Sustainability Research Institute. When I was invited to join an international review led by the University of Surrey’s Global Centre for Clean Air Research (GCARE), I realised others were asking the same thing. More than 50 authors, including researchers and stakeholders from around the world, came together for this project, that discovered a surprising truth: We’re great at celebrating the benefits of GBI, but not so great at understanding the barriers that keep them from succeeding in urban environments. After screening nearly 29,000 publications and synthesising over 500 studies, we realised that these barriers aren’t just environmental or financial. They’re social. Cultural. Political. Structural. Often invisible, always interconnected.

Oxhey Park, Bushey, Watford.

This review then developed an integrative framework that unites fragmented knowledge across four key domains of GBI implementation: environmental, social, economic, and governance/policy barriers. The result is the most comprehensive review about the barriers slowing the implementation of GBI, and most importantly, provides 12 actionable recommendations to overcome them. Some of the findings:

1.      Environmental barriers

Planting trees, restoring rivers, or adding wetlands might seem straightforward, but there are major environmental challenges, including:

• The risk of unintended consequences, like tree shading reducing solar energy output or pollen emissions.

• A lack of interdisciplinary research linking ecology with human behaviour and adaptation

• Concerns around allergens, water quality, or soil pollution

• Limited understanding of long-term thermal performance and microclimate dynamics

• Plant species that struggle to survive urban stressors

• In other words, not all GBI automatically creates resilience. Without data-driven design, careful species selection, and long-term monitoring, even well-intentioned GBI can go wrong.
  

2.      Social barriers

Here’s the part cities often overlook: GBI doesn’t succeed without people. If GBIs are built without community participation, or without attention to justice and accessibility, they can unintentionally increase inequality, such as: 

• Green gentrification pushing out low-income residents

• Designs that prioritise aesthetics over community needs

• Lack of cultural relevance or integration of local/traditional knowledge

• Poor public understanding of multifunctional landscapes

• When communities co-create GBI, it becomes more than infrastructure, it becomes identity, belonging, and wellbeing.
  

3.      Economic barriers

Everyone may agree that GBIs are valuable. But do we value them economically? GBI is chronically underfunded because:

• Ecosystem services are hard to quantify

• Conventional economic models overlook long-term benefits

• Financing mechanisms don’t fit nature-based solutions (GBI)

• ESG metrics remain inconsistent or unclear

The study argues for better valuation tools, innovative financing, and standardised metrics that capture health, cultural, and biodiversity benefits, not just short-term costs for projects.

4.      Governance/policy barriers

Even when the science is strong and the community is ready, policy can make or break GBI. Common governance obstacles include:

• Competing land uses in dense urban areas

• Unpredictable regulations and low political prioritisation

• Fragmented leadership and siloed departments

• Reliance on traditional grey infrastructure

Yet smart policy can unlock huge potential. Think green roofs, pocket parks, vertical gardens, permeable surfaces, solutions that make space within the city rather than pushing beyond it. What cities need is clear governance, cross-sector collaboration, and adaptive, science-informed policies that treat GBI as essential urban infrastructure and an important part of our urban planning.

So what now?

We identified the barriers and with the input of the great team we conclude the review with 12 recommendations for transforming GBI from fragmented elements into truly multifunctional, resilient, community-driven systems. A few recommendations:

• Strengthen interdisciplinary collaboration to overcome siloed GBI approaches

• Use AI, remote sensing, and microclimate modelling to optimise design

• Integrate thermal adaptation and vulnerability information into GBI planning

• Centre equity, culture, and community co-governance

• Promote cross-disciplinary collaboration to align GBI design with community realities

• Develop standardised ESG metrics and innovative financing

• Adopt micro-scale, three-dimensional solutions for land-efficient greening

Graphical abstract (Overlooked Considerations in Prescribing Green and Blue Infrastructure Solutions for Urban Environm…)

It’s not about adding more GBI, it’s about integrating it smarter, more inclusively, and more strategically. As climate change intensifies, the future of urban sustainability and resilience will depend on whether cities can build GBI that truly works for the environment and for the people who call these cities home.

By Karina Corada Perez